Tracheotomy instrument



y 1961 c H. SHELDEN ETAL 2,991,787

TRACHEOTOMY INSTRUMENT Filed April 11, 1957 2 Sheets-Sheet 1 W405i H. GOODW/N 505 14. MIA/DEED C. #UNTEE SHELDEA/ l'lvvslvraes.

July 11, 1961 c H. SHELDEN ETAL 2,991,787

TRACHEOTOMY INSTRUMENT Filed April 11, 1957 2 Sheets-Sheet 2 Wm 7'52 ,4. Gavan 0v 80a AKA 02:0 C. HUNTER SHELDEN United States Patent 2,991,787 TRACHEOTOMY INSTRUMENT C Hunter Shelden, Pasadena, Walter H. Goodwin, Sierra Madre, and Bob A. Kindred, Duarte, Calif.; said Walter H. Goodwin and said Bob A. Kindred assignors. to Sierra Engineering Co., Sierra Madre, Los Angeles, Calif., a corporation of California Filed Apr. 1'1, 1957, Ser. No. 652,227 '10 Claims. (Cl. 128351) The invention relates to surgical instruments and has particular reference to an instrument frequently desig nated a tracheotome or tracheotomy instrument which consists of an arcuate tube containing a knife-like insert which can be injected into the throat or trachea to make it possible for a person to breathe under conditions where the upper portion of the throat might be stopped for any reason.

Although operations of the trachea have long been practiced by surgeons, instruments available to medical men have been such as to require a great degree of skill and technique in their use to insure the safety of the person upon whom the operation is to be performed. Even in the hands of skilled surgeons troublesome condiditions can arise to the detriment of the patient. As in all cases where incisions are made in the body of an individual, inner tissues and cartilage as well as outer tissues and skin are aggravated by the presence of foreign elements in the wound and moreover after the last instrument has been withdrawn, the wound upon healing tends to leave a scar. When such a wound is on a visible portion of the body as, for example, the neck or throat, a large area of scar tissue becomes unsightly and extremely objectionable. Further still, when a tracheotomy tube inserted in the trachea must be worn for a considerable period of time, if the tube is not properly designed and I properly inserted, the ensuing discomfort is not only disturbing to the patient but is apt to impair recovery to an objectionable degree.

- Employment of the technique heretofore practiced has indicated certain disadvantages, especially where the tracheotomy instrument is intended to be included in firstaid kits where use of the instrument may become necessary under somewhat adverse conditions and perhaps by persons not specially trained in the handling of instruments of such character.

It is therefore among the objects of the invention to provide instrumentation for the performance of a tracheotomy which embodies simplicity of design, ease of handling, and which is of such character that it is direct,

compact, and thereby especially effective for quick first aid work under adverse conditions in the hands of competent though perhaps not specially skilled technicians.

Another object of the invention is to provide a new and improved tracheotomy instrument, all parts of which fit snugly one with respect to the other with those parts needing manipulation by the fingers made large so that the instrument can be firmly grasped during manipulation, thereby minimizing the danger of slipping and improving the speed with which the device can be used. Still another object of the invention is to provide a new and improved tracheotomy instrument where in cutting trocar is so designed that a certain amount of inherent resiliency is made use of in fitting the trocar within the tube so that the two when used together are in eflfect a single instrument.

.Still another object of the invention is to provide a new and improved fastening means for securing the trocar in a tube which has a progressive tightening and loosening action and which is so constructed that it cannot be inadvertently disconnected during use, thereby minimizing unnecessary movement of the instrument when in the body of a patient.

A further object still is to provide a new and improved tracheotomy instrument wherein the trocar blade is so constructed that it has a progressive cutting action as it enters the trachea, the blades being designed to make incisions at right angles to each other under circumstances wherein a short blade acting at right angles to the action of a long blade is provided with a smooth counter-acting portion of the bulb, the location and size of which assists in the making of a smooth secondary incision large enough to easily accommodate the tube which follows the knife but made in such fashion that after the entire instrument is withdrawn the healing of the wound will leave no more than a minimum amount of scar tissue.

A still further object is to provide in instrumentation for a tracheotomy a guide incisor for finding and making a initial incision whereby to guide the cutting trocar in the making of the principal incision, the guide incisor being so constructed that passage of air entirely through the incisor aids in a preliminary relief of the patient, the incisor being further so constructed that the technician can interconnect the trocar with the preliminary incisor with utmost ease and rapidity.

Still further among the objects of the invention is to provide a new and improved instrumentation for tracheotomies wherein the tube designed to be temporarily left in the trachea of the patient is so constructed as to be provided with a series of replaceable inner cannula removable for cleaning at repeated intervals without in any way impairing the eifectiveness of use of the tube and with a minimum of disturbance and discomfort to the patient.

With these and other objects in view, the invention consits in the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

, In the drawings:

FIGURE 1 is a perspective view of the combined instruments in the positions assumed immediately prior to. insertion of the trocar along the guide incisor into the trachea of a patient. 7

FIGURE 2 is a fragmentary longitudinal sectional view of the working ends of the instruments in positions occupied during initial steps of the operation.

FIGURE 3 is a longitudinal sectional view of the trocar assembly after withdrawal of the preliminary incisor and prior to withdrawal of the trocar instrument.

FIGURE 3a is a cross-sectional view taken on the line 3a of FIGURE 3.

FIGURE 4 is a fragmentary sectional view taken on the line 44 of FIGURE 3.

FIGURE 5 is a cross-sectional view taken on the line 5-5 of FIGURE 3.

FIGURE 6 is a longitudinal sectional view of the tube with a removable insert or inner cannula applied therein.

FIGURE 7 is a perspective view of the trocar assembly. FIGURE 8 is a cross-sectional view on the line 88 of FIGURE 7.

FIGURE 9 is a perspective view of one of the removable inner cannulae.

In an embodiment of the invention chosen for the purpose of illustration a tube assembly 10 containing a trocar assembly indicated generally by the reference char-. acter 11 is designed to be guided by a needle assembly 12 in the insertion of the tube in a trachea 13 of a person The needle assembly consists of a knob 18 having the form"of a'somewhat elongated cylindrical element, at the outer end of which is a knurled flange 19. The flange is larger in diameter in order to be easily grasped between the thumb and forefinger of the surgeon. A bore'20 textends clear through the. knob 18 and at" its inner end is enlarged to a slight degree for'reception of a needle 21. Theneedle has a bore 22 extending throughout its length and throughout the portion of the needle which is exposed beyond the'knob there is provided acontinuous channel 23 open at the outer end and at the inner end of which is an enlargement 24 substantially as wide as the diameter of the bore 22 and'having a length about twice thediarneter of the bore. The needle is provided with a wedge-shaped cutting end 25, the edges of which are offset slightly with respect to the axis of the needle, there being provided a bevelled portion 26 between the cutting edges and the outer end of the channel 23.

The tube assembly comprises in the main an arcuate tube 30 having a central passage or lumen 31. An inner end 32 of the tube is bevelled for a short distance to provide a feather edge. The bevelled end 32 is pressed inwardly to a slight degree so that the inside diameter of the bevelled end is slightly smaller than the inside diameter of the passage or lumen 31. Lateral slots 33 and 34 extend throughout the entire length of the bevelled end 32 and into that portion of the tube which is at full diam eter. A transverse slot 35 extends for a similar distance and lies in a direction at right angles to the plane of the lateral slots 33, 34. At the opposite or outer end the tube 30 is provided with a plate 36. The plate has a cupshaped periphery 37 and is provided with openings 38 in which a tape may be tied in order to anchor the plate and tube to the neck of the patient after insertion. Studs 40 are secured to the bottom of the plate 36 on diametrically opposite sides by means of rivets 41. A flange 42 forming the outer end of the tube 30 has cut out portions 43 to allow the flange to fit around a base 44 of each of the studs and beneath shoulders 45 of the respective studs so that the flange can be retained in place within the plate by the overlying shoulders 45. It will be noted that the depth of the base 44 is substantially greater than the thickness of the flange 42 to provide a substantial amount of freedom of motion between the plate and the tube so that the plate can be tilted in various directions with respect to the axis of the tube, thereby to permit the plate to lie easily in contact with the exterior of the throat without the stiffness which would be present should the plate and tube be fixed one with respect to the other.

Each stud is provided with a gently bevelled portion 46 between the shoulder and the outer circumference of the large cylindrical portion of the stud.

The trocar assembly 11, shown to better advantage in FIGURE 7, consists of a handle knob 50 relatively large in diameter for being easily grasped betweenthe thumb and forefinger of the technician and knurled at 51 to improve the grip. A swivel block 52 has a snug swivel fit in a suitable aperture 53 within the handle knob. To confine the block rotatably within the knob the block is provided with an annular recess 54 and a pin 55 is extended through the knob into the recess. To facilitate withdrawal of the pin a pin hole 56 is provided in the block and a pin hole 57 in the knob in alignment with the pin makes it possible to knock the pin out of position with a suitable tool. It will be obvious, however, to those skilled in the art that the swivel connection shown and described as being between the knob 11 and rod 61, may be provided between the rod 61 and the bulb at the lower end of the rod with equal facility.

On the knob is a lock flange 57 spaced from the main portion of the knob by an annular depression 58. Flat sides 59 of the lock flange enable the handle knob to be pushed into position and enable the lock flange to be inserted past the heads of the studs 40, after which the handle knob can be rotated until astop pin 60 is brought into contact with one of the studs, at which time the handle knob is prevented from further rotation.

An arcuate rod 61 is anchored to the swivel block 52 and has approximately the arcuate shape of the tube 30. At the other end there is fastened to the rod a bulb indicated generally by the reference character 62. The bulb comprises a collar 63 and a portion often described as an olive seed. The last defined portion is of some one composite shape in that one side portion 64 has a smooth long taper and the opposite side portion 65 has a smooth taper substantially shorter. It will be noted, however, that the curvature of both portions, through different, is such that the outer surfaces of those portions are tangent to the bevelled end 32 of the tube 30 when the trocar is located within the tube. Between the portions 64 and 65 is a blade slot 66 in which is anchored a flat arcuate blade 67. This may be appropriately described as the long blade. As more clearly shown in FIGURE 7 the long blade is tapered from a width at the large end substantially equal to the section of maximum diameter of the bulb 62 to practically a point at the outermost end. At the very point or tip there is provided a ball 68. -Itwill be noted that the arcuate shape of the long blade 67 follows substantially the arcuate direction of the tube 30.

A short blade 70 has a forwardly directed convex cutting edge 71. The short blade is approximately half the length of the long blade and is received in an appropriate blade slot 72 in the side portion 65. The short blade lies at right angles to the long blade and being fastened thereto at an edge 70', as indicated in FIGURE 8, by appropriate means serves as a stiffening medium for the long blade. The long blade may also be secured by welding 73 or other appropriate means to the side portion 64.

Of particular importance is the location of the short blade with respect to the side portion 64 in that the progressive increase in depth of the side portion corresponds to the progressive increase in width of the short blade whereby as the short blade proceeds to cut, the point of cutting pressure is backed up by the immediately opposite smoth surface of the side portion 64.

It is also important to note that the width along cutting edges 69 of the long blade at its widest portion is substantially the same as the inside diameter of the tube 30 at the area of maximum diameter. Similarly the width or depth of the short blade at its end Where the depth is greatest is such as to position the cutting edge approximately flush with the inside diameter of the tube 30 at the area of maximum diameter. Having the large ends of both blades as large as described, a maximum cut is effected in the tissues, thereby improving the ease of insertion of the tube into the incision.

Once inserted into the trachea and the trocar assembly withdrawn, the tube 30 occupies the position shown in FIGURE 6. While so located an inner cannula or disposable tube 75 may be inserted. The inner cannula may be of an appropriate plastic or some other more readily disposable material which will be entirely safe but which is sufficiently inexpensive that it can be disposed of and replaced after becoming coated with secretions. If preferred the inner cannula may be of some material which can be sterilized and reapplied.

As shown to good advantage in FIGURE 6 and 9 the inner cannula consists of a tubular portion 76 and an integral flanged portion 77. It'Will be noted that a end 78 conforms to the inwardly depressed beveled in terior of the tube 30 at the end 32. The length of the tubular portion is such that the bevelled end 78 is substantially flush with the edge of the bevelled end 32 of the tube when the flanged portion 77 lies against the bottom of the plate 36. -The flanged portion fixes the position of the inner cannula when in position within the tube and also facilitates grasping the-inner cannulafor removal when replacement is needed.

.The bevelled portion .78 .isalso of assistance inlining up the inner cannula within the tube 30. The aligning feature is also present in the provision of the long gentle taper on the bulb 62.

In the operation of the instruments herein described a proper point of application on the trachea of the patient is selected by feeling for a space between tracheal cartilages 17 below the larynx. Customarily the operation is performed with the technician positioned above the head and shoulders of the patient. The point of the needle 21 is inserted at the proper location and pushed into the trachea. The proper amount of insertion can be readily detected by the passage of air from the trachea through the bore 22 of the needle and the bore 20 of the knob 18. Only a sufiicient portion of the needle is inserted into the trachea to make a hole into the lumen of the trachea. The needle is then held steady and the ball 68 of the long blade is inserted into the enlargement 24 in the relative positions of parts illustrated in FIG- URES 1 and 2. The long blade is subsequently tilted to the dotted position 67' shown in FIGURE 2, which is the position occupied while the trocar is being pushed into the trachea to make the incision. It should be noted in this connection that the tube 30 and trocar 11 are joined as shown in FIGURES l and 3. The joining, it will be understood, has previously been accomplished by inserting the bulb 62 into the tube to the position shown in FIGURE 3, at which point the handle knob 50 is applied so that the flat sides 59 pass the studs, after which the handle knob is rotated until the stop pin 60 is brought against one of the studs. As the handle knob is rotated, the lock flange is gradually forced against the bevelled portions 46 of the respective studs 40, which motion gradually eases the lock flange into locked position. In that position a slight tension is placed upon the rod 61, springing the rod outwardly so as to snugly engage opposite ends of the trocar assembly with the tube.

After the long blade edges have begun the incision, and the ball 68 has emerged from the bore 22 of the needle, the needle is withdrawn, the trocar and tube combination is rotated to the relative position illustrated in FIGURE 3 with respect to the trachea, and the final thrust is made, during which action the short blade 70 as well as the long blade 71 proceeds with the cutting action. A three-way incision is thus made, which incision has substantially the shape and direction of the blades as illustrated in FIGURE 8. By reason of the streamlined configuration of the bulb and bevelled end 32 of the tube, the tube follows the bulb into the trachea smoothy and with a minimum of disturbance. The ball 68 prevents any injury to the inside Walls of the trachea. After the tube and trocar assembly have been inserted to the positions illustrated in FIGURE 3, the knob 50 is rotated counter-clockwise as viewed in FIGURE 5 until the flat sides 59 enable release of the handle knob, .at which time the trocar assembly is withdrawn leaving the tube 30 in place. Once in place the inner cannula 75 can be inserted and the tube and cannula left. in the trachea for as long as need be. Removal and replacement of the cannula permits use of the tube in the trachea long enough to accomplish the desired purpose.

There has accordingly been described herein an improved type tracheotomy instrument or instrument set which in the form and assembly referred to is such as to be easily manipulated with a minimum prospect of slipping in the hands of the technician so that the operation can be performed quickly and accurately as is often requisite and with a prospect of unnecessarily wounding of the patients throat.

While we have herein shown and described our invention in what we have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of our invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A tracheotomy instrument set comprising a tubular needle having a sharp wedge-shaped end having a bore therethrough, a knob having a bore therethrou'gh, said needle being anchored in the knob with said bores in coinmunicationwith each other, a continuous open channel communicating with the bore in said needle from the wedge-shaped end to a portion thereof adjacent the knob, said channel having a laterally and longitudinally extending enlargement at the end adjacent the handle, and a trocar and tube combination comprising an arcuate tube, a trocar assembly in said tube comprising a handle element adapted to releasably engage an outer end of said tube, a resilient arcuate rod, a bulb element on the end of the rod remote from the handle element, a swivel connection between said rod and one of said elements, an arcuate fiat blade in said bulb element and protruding endwardly thereof, said blade having opposite surgically sharp edges tapering to a free pointed end and a smooth ball anchored on said end, said ball being substantially smaller in diameter than the length and breadth of said enlargement and larger in diameter than the width of said channel, said ball being releasably received in said enlargement and releasably engaged in said channel thereby to retain the pointed end of said blade in the bore of said needle during an initial incision.

2. A tracheotomy instrument set comprising a tubular needle having a sharp wedge-shaped pointed end and a bore therethrough, a knob having an axial bore therethrough, said needle being anchored in the knob with said axial borein communication with the bore of the tubular needle, a continuous open channel in said needle from the pointed end to a portion thereof adjacent the knob, said channel having a laterally and longitudinally extending enlargement at the end adjacent the knob, and a trocar and tube combination comprising an arcuate tube, a trocar assembly in said tube comprising a handle adapted to releasably engage an outer end of said tube, an arcuate rod, a swivel block rotatably mounted in the handle, a bulb on the end of the rod remote from the handle, a short blade in said bulb extending forwardly therefrom, an arcuate flat long blade in said bulb and protruding endwardly thereof and beyond the short blade, said long blade having opposite surgically sharp edges tapering to a free pointed end and a smooth ball anchored on saidend, said ball being substantially smaller in diameter than the length and breadth of said enlargement and larger in diameter than the width of said channel, said ball being releasably received in said enlargement and releasably engaged'in said channel thereby to retain the pointed end of said blade in the bore of said needle during an initial incision. I

3. A tracheotomy instrument comprising an arcuate tube having an outwardly extending outside end and an inside end, a plate, studs on the outer face of said plate on opposite sides of the center of said plate and having means thereon normally overlying the outside end of said tube, said inner end having a tapered and feathered edged tip directed inwardly toward the axis and a plurality of longitudinal blade slots extending throughout said tapered tip, and a trocar assembly releasably received in said tube comprising a rounded bulb having a section of maximum diameter greater than the smallest diameter of said tip, a long blade secured between opposite sides of said bulb and substantially filling opposite blade slots in said tip and a transverse short blade ubstantially filling a blade slot intermediate said opposite blade slots, a handle, an arcuate rod having attachments at respective opposite ends to said bulb and said handle, one of said attachments comprising a rotatable connection, a lock flange on-the handle having a clearance whereby to pass said studs, said fiange having an assembled position releasably engaging said studs.

4. A tracheotomy instrument comprising an arcuate tube having an outside end and an inside end, a plate, studs on the outer face of said plate on opposite sides of the center of said plate and having shoulders thereon normally loosely overlying the outside end of said tube, said inner end having a tapered tip directed inwardlyitoward the axis, and a trocar assembly releasably received in said tube comprising a rounded bulb having cutting blades and having a section of maximum diameter greater than the smallest diameter of said tapered tip, a handle, a swivel block, an arcuate rod secured at respective opposite ends to said bulb and said swivel block, said swivel block having a rotatable mounting in said handle, a lock flange on the handle having relieved portions, said lock flange having an assembled position releasably underlying the shoulders of said studs, the length of said rod being slightly in excess of the arcuate axial distance between the extreme positions of the bulb in said tapered tip and said swivel block when said knob is in engagement with said studs whereby said rod is sprung slightly thereby to maintain the trocar assembly snugly within said tube.

5. A tracheotomy instrument comprising an arcuate tube having an outside end and an inside end, a flange on the outside end, a plate, studs on the outer face of said plate on opposite sides of the center of said plate and having shoulders thereon normally loosely overlying said flange, and a trocar assembly releasably received in said tube and comprising a rounded bulb having cutting blades mounted thereon and extending endwise therefrom, a handle, a swivel block, an arcuate rod secured at respective opposite ends to said bulb and said swivel block, said swivel block having a rotatable mounting in said handle, a lock flange on the handle having relieved portions, said studs each having a head and a tapered portion between said head and said shoulder, said relieved portions being adapted to pass said studs and said lock flange being adapted to progressively advance along said tapered portions to a position beneath said shoulders and to retract therefrom, and a stop element on said handle having an engagement against one of said studs in assembled position whereby to stop rotation of said handle in a locked position.

6. In a tracheotomy instrument an arcuate tube having an outside end and an inside end, a flange on the outside end, a plate, studs on the outer face of said plate on opposite sides of the center of said plate and having shoulders thereon normally loosely overlying said flange and providing thereby a relatively loose attachment of said plate on said flange, said inner end of the tube having a gently tapered tip terminating in a feathered edge directed inwardly toward the axis and longitudinal blade slots extending throughout said tapered tip to the portion of the tube of maximum diameter, and a trocar assembly releasably received in said tube and comprising a circumferentially rounded and elongated bulb having a section of maximum diameter adjacent an inner end, the said maximum diameter being greater than the smallest diameter of said tapered tip, an endwardly open slot in said bulb, a long blade secured in said slot and substantially filling the length and breadth of opposite blade slots in said tip and a short transverse blade substantially filling the length and breadth of a blade slot intermediate said opposite blade slots, a handle, a swivel mounting, an arcuate rod secured at respective opposite ends to said bulb and said swivel mounting, said swivel mounting having a rotatable connection in said handle, a lock flange on the handle, said studs each having a head and a tapered portion between said head and said shoulder, said flange having an operating position underlying said tapered portions, the length of said rod being slightly in excess of the arcuate axial distance between the extreme positions of the bulb in said tapered tip and said swivel mounting when said handle is in engagement with said studs whereby said rod is sprung slightly under tension thereby to maintain the trocar assembly snugly withinlsaidtube, and a stop element on said handle in engagement against one of said studs in operating position whereby to stop rotation of said handle in one direction at a point of engagement with said studs.

7. In a tracheotomy instrument tube and trocar combination adapted for insertion into the trachea and comprising an arcuate tube, a trocar assembly releasably received in the tube during insertion and thereafter with drawn, said trocar and comprising a handle providing a finger hold, an arcuate rod swivelly mounted at one end in said handle, a bulb on the end of said rod remote from the handle, said bulb having a smooth long tapered side and an opposite smooth short tapered side, said sides being adapted to extend outwardly of the end of said tube, a long blade having a flat arcuate form of progressively diminishing breadth from a base to a point end, said base being anchored in said bulb, said blade having a blunt element on said point end, a short blade at right angles to said long blade and anchored in said short tapered side of the bulb, said long tapered side of the bulb having a progressively increasing depth from the outer end toward the inner end and said short blade having a progressively increasing depth corresponding to the progressive increase in depth of the short tapered side, said short blade having an engagement with the long blade for about one-half the length of the long blade.

8. In a tracheotomy instrument a tube and trocar combination for insertion into the trachea comprising an arcuate tube, a trocar assembly releasably retained in the tube during insertion and thereafter withdrawn, said trocar assembly comprising a handle providing a finger hold, a swivel block rotatably mounted in said handle, said block having an annular groove therein and a pin rotatably anchoring said block in said handle, an arcuate rod on said block, a bulb on the end of said rod remote from the block, said bulb having a smooth long tapered side extending outwardly of the tube during said insertion and an opposite smooth short tapered side extending outwardly of said tube a distance less than said long tapered side during said insertion, said bulb having a slot between said sides, a long blade having a flat arcuate form of diminishing breadth from a base end to a point end, the concave face of said blade being turned toward said short tapered side, said base end being anchored in said slot, opposite cutting edges on said blade and a rounded ball on said point end, said cutting edges at the base having a distance therebetween substantially equal to the inside diameter of said tube, said short tapered side having a central longitudinal slot at right angles to said first solt, a short blade at right angles to a concave face of said long blade and anchored 1n said longitudinal slot, said short blade having a forwardly convex cutting edge and a depth at the base adapted to extend said cutting edge to the inside circumference of said tube, said short blade having substantially half the length thereof extending forwardly beyond said short tapered side, said long tapeerd side of the bulb having a progressively increasing depth from the outer end toward the inner end and said short tapered side havmg a progressively increasing depth corresponding progressively to the progressive increase in depth of the short blade and located opposite thereto, said short blade being in engagement with the long blade for about one-half the length of the long blade.

9. A tracheotomy instrument comprising a needle having an axially extending bore formed therein, the bore being open at one end of the needle, the needle having a longitudinally extending channel formed therein extending from said one end of the needle to adlacent he P- posite end of the needle, the channel being open to the bore throughout the length of the channel, the dlameter of the bore being greater than the Width of the channel, the needle having a channel enlargement formed therein open to the channel and spaced from said one end of the needle, the channel enlargement being larger in its transverse dimensions than the width of the channel, and a trocar having an inner end and an outer end and a cutting blade adjacent its inner end, the inner end of the trocar having an enlargement receivable in the needle bore through said channel enlargement and being of a size such that it may not be removed radially outwardly from the needle through the channel, whereby the trocar enlargement is slideable axially in the needle bore from the channel enlargement and out through the said one end opening of the needle.

10. A tracheotomy instrument comprising a needle having an axially extending bore formed therein, the bore being open at one end of the needle, the needle having a longitudinally extending channel formed therein extending from said one end of the needle to adjacent the opposite end of the needle, the channel being open to the 20 bore throughout the length of the channel, the diameter of the bore being greater than the width of the channel, the needle having a channel enlargement formed therein open to the channel and spaced from said one end of the needle, the channel enlargement being of larger transverse dimensions than the Width of the channel, a trocar having an inner end and an outer end, the inner end of the trocar having an enlargement receivable in the needle bore through said channel enlargement and being of a size such that it may not be removed radially outwardly from the needle through the channel, whereby the trocar enlargement is slideable axially in the needle bore from the channel enlargement and out through the said one end opening of the needle, and an open ended tube having an inner end and an outer end, the trocar being receivable in the tube with the trocar enlargement extending out beyond the inner end of the tube and the outer end of the trocar extending out beyond the outer end of the tube, the trocar being withdrawable from the tube out through the outer end of the tube.

References Cited in the file of this patent UNITED STATES PATENTS 2,786,469 Cohen Mar. 26, 1957 FOREIGN PATENTS 146,305 Austria June 25, 1936 

